There have recently been image formation devices including a document box with function of storing pieces of document data and a network communication with function of downloading a piece of document data existing on an external server on the Internet. Such an image formation device keeps downloaded pieces of document data stored in a document box and performs printing of them as needed. In this case, because no updates of the pieces of document data made on the external server side are reflected on the pieces of document data downloaded to and stored in the document box, the old versions of the pieces of document data may be printed as they are even though the pieces of document data on the external server side have been updated. To cope with this, it has been proposed to check, by polling at regular intervals, the updated times and dates of the pieces of document data represented by link information and, if a renewed piece of document data is detected and if necessary, download the renewed piece of document data again (see Patent Literature 1).